When Bonanza Creek Energy Inc., a 17,000 boed producer that typically runs plug and perf completions in the (Denver-Julesburg Basin, started considering a cemented sliding sleeve solution for seven stand-alone lease-saving wells, it had some expectations and plenty of reservations.
Cemented sliding sleeves promise shorter fracking times, better stimulation at the toe of the well and potentially better production results. But, like many operators, Bonanza also had misgivings about trying a new approach: Would the tools get to total depth? Would wiper runs effectively clear the cement? Would the sleeves open properly?
The case for cemented sliding sleeves
Cemented sliding sleeve completions are winning acceptance across North America’s shale basins because they are fast, efficient and can improve production. But it’s still a niche technology that is building a track record of success.
Since commercial introduction in 2012, cemented sliding sleeve completions have taken hold in four niches, according to Dwayne DuBourdieu, COO at Tartan Completions, a company with 20 years of engineering and manufacturing experience in downhole solutions, and a leader in ball-drop cemented sliding sleeve technology.
These are the niches:
- Hybrid completions in extended reach horizontals where sleeves provide efficient and reliable stimulations at the toe of the well
- Standalone wells that don’t benefit from multi-well plug and perf operational efficiencies
- Short laterals
- Limited entry completions
“As a sleeves guy, I’d love to put sleeves in every single well, but this is what the industry allows us to do right now,” DuBourdieu says.
The use of ball-drop cemented sliding sleeves in the U.S. continues to grow, but upfront costs of this technology can be a deterrent.
Resistance to change is another hurdle.
“Operators are generally reluctant to change from proven techniques” says Tim Leshchyshyn, president of FracKnowledge, a fracture engineering consulting and frac database group that operates internationally. “When operators don’t have to change, they often continue innovating down the same branch of the tree.”
Citing numbers that Leshchyshyn presented as chair of a recent Houston oil and gas conference, he says about 85 per cent of U.S. horizontal laterals use plug and perf completions. The rest uses something “a little fancier,” including ball drop and coil tubing-actuated sliding sleeves.
Almost the reverse trend is the case in Canada, where almost 75 per cent of operators use other completions than plug and perf. But plug and perf is gaining in Canada, especially in emerging plays such as the East Duvernay, a true shale often described as an Eagle Ford analogue.
“One thing I will tell you about sliding sleeves, and it doesn’t matter whether it’s cemented or open hole, is that they are very fast and efficient,” Leshchyshyn says.
As the industry drills longer extended-reach laterals, plug and perf completions face challenges to wireline retrieval and effective stimulation at the toe of multi-mile wells. This is forcing operators to take a fresh look at completions technologies.
In its short history, ball-drop cemented sliding sleeve completions have come a long way in providing reliable efficiency gains. A risk this technology had to overcome was to ensure that cementing operations didn’t interfere with the ability of sleeves to slide open. Stuck sleeves are costly to remedy or bypass (lost production).
Different companies have different ways to avoid stuck sleeves—cement retarder, sleeve placement to minimize cement exposure, etc.
Having seen many of these problems firsthand as a downhole milling service provider, Tartan Completions designed a simple and reliable solution: its patented BurstPoint rupture discs completely isolate the sliding sleeves from the cementing operation.
BurstPoint rupture discs also create a closed system while pumping actuations balls so there is no fluid loss to the formation as the ball travels from sleeve to sleeve.
“When it hits the final sleeve, that ball stops to isolate the other stages. Then you pressure up to another threshold and that ruptures the BurstPoint discs,” DuBourdieu says. “We’ve never had a sleeve fail.”
Another issue some sliding sleeve solutions address is uneven frac distribution. In plug and perf stimulations, the force of pressurized frac fluid loaded with proppant can erode the edges of the perforated holes in the cemented casing as the fluid seeks the path of least resistance.
By incorporating machined erosion rings, Tartan’s BurstPoint technology delivers uncompromised execution of the frac design by preventing hole erosion and resulting change in hole size during fracturing. This can often lead to double-digit percentage improvements in production compared to plug and perf sections in hybrid wells.
Bonanza Creek results
Bonanza chose Tartan Completions for its seven stand-alone wells because of the service provider’s technical expertise on completions design, says Joel Dill, Bonanza’s manager, drilling and completions.
“They worked with us and provided targets for what we should see on a per stage basis for treating pressures and max rate. We ran almost 100 tools in each of these wells, so we had a lot of skin in the game,” Dill says.
All of Bonanza’s concerns about Tartan’s sliding sleeve technology were put to rest by the fracking results. All Multifrac sleeves opened properly, fracked and the wells reached production targets.
The effectiveness of sliding sleeve stimulations was underscored in one of the seven wells where fracking was stopped due to a casing breach at the top of a curve in the well after 21 stages. The breach was patched and the well was put on production with only 21 treated stages.
As a result, all the stages in this well were MultiFrac stages and the results proved to be the best production per 1000 feet in the company. It was also the most productive well of the seven, producing over 10,000 bbls/1000 lateral feet in its first six months.
”As the industry moves to longer and longer laterals—three, three-and-a-half mile laterals—wireline runs don’t make sense,” Dill says. “So a system like Tartan’s, I think, can efficiently and economically take the place of that.”
Cemented sliding sleeve technologies continue to win market share, but that progress will depend, in part, on operator willingness to try different approaches. As more operators prove the reliability and bottom-line advantages of cemented sliding sleeve completions, wider acceptance is inevitable.
Contact Tartan Completions